
An ideal gas has a volume of
at a pressure of
and a temperature of
, as shown in the figure below.
The gas suddenly expands to a volume of
. During the expansion, no thermal energy is transferred. The final pressure of the gas is
at temperature
, as shown in the figure above.
Show that the number of gas molecules is
.
Show that the final temperature
of the gas is
.
The average translational kinetic energy
of a molecule of an ideal gas is given by

where
is the thermodynamic temperature and
is the Boltzmann constant. Calculate the increase in internal energy
of the gas.